A parametric experimental study has been conducted to investigate the effect of
polypropylene fiber on the fracture properties of concrete containing fly ash and silica fume, with five fiber
volume fraction (0.04, 0.06, 0.08, 0.1 and 0.12%) used. The results indicate that the addition of
polypropylene fiber has greatly improved the fracture parameters of concrete composite containing 15% fly ash
and 6% silica fume, such as fracture toughness, fracture energy, effective crack length, maximum mid-span
deflection, the critical crack opening displacement and the maximum crack opening displacement of the three-point
bending beam specimens. When the fiber volume fraction increases from 0 to 0.12%, the fracture parameters
increase gradually with the increase of fiber volume fraction. The variation rules of the fracture parameters indicate
that the capability of polypropylene fiber to resist crack propagation of concrete composite containing 15% fly ash
and 6% silica fume is becoming stronger and stronger with the increase of fiber volume fraction with the fiber
volume fraction not beyond 0.12%.